Write head having non-magnetic write gap seed layer, and method

ABSTRACT

In accordance with one embodiment, an apparatus includes a main pole layer of magnetic material; a second layer of magnetic material; a first gap layer of non-magnetic material disposed between the main pole layer and the second layer of magnetic material; a second gap layer of non-magnetic material disposed between the main pole layer and the second layer of magnetic material; wherein the second gap layer of non-magnetic material is disposed directly adjacent to the second layer of magnetic material. In accordance with one embodiment, this allows the gap to serve as a non-magnetic seed for the second layer of magnetic material. A method of manufacturing such a device is also described.

BACKGROUND

Processing steps are often used to form magnetic elements, such asmagnetic recording heads used in the disc drive industry. Theperformance of magnetic elements can be influenced by the orientationand separation with respect to other magnetic elements. Thisparticularly can be true as magnetic elements are placed in closerproximity to one another.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Otherfeatures, details, utilities, and advantages of the claimed subjectmatter will be apparent from the following more particular writtenDetailed Description of various implementations and implementations asfurther illustrated in the accompanying drawings and defined in theappended claims.

In accordance with one embodiment, an apparatus can be configured thatincludes a main pole layer of magnetic material; a second layer ofmagnetic material; a first gap layer of non-magnetic material disposedbetween the main pole layer and the second layer of magnetic material; asecond gap layer of non-magnetic material disposed between the main polelayer and the second layer of magnetic material; and wherein the secondgap layer of non-magnetic material is disposed directly adjacent to thesecond layer of magnetic material. In accordance with one embodiment,this allows the gap to serve as a non-magnetic seed for the second layerof magnetic material.

In another embodiment, a method can be utilized that includes depositinga main pole layer of magnetic material; depositing a first gap layer ofnon-magnetic material; depositing a second gap layer of non-magneticmaterial; and depositing a second layer of magnetic material directlyadjacent to the second gap layer of non-magnetic material so that thesecond gap layer of non-magnetic material is disposed between the mainpole layer of magnetic material and the second layer of magneticmaterial.

These and various other features and advantages will be apparent from areading of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presenttechnology may be realized by reference to the figures, which aredescribed in the remaining portion of the specification.

FIG. 1 illustrates an example diagram of a disc drive system with across-section of a substantially uniform write gap, in accordance withone embodiment.

FIG. 2A illustrates an initial layer of magnetic material for use informing a main pole, in accordance with one embodiment.

FIG. 2B illustrates a beveled edge formed on the initial layer ofmagnetic material, in accordance with one embodiment.

FIG. 2C illustrates an initial layer of material for use in the gapbetween two magnetic layers of material, in accordance with oneembodiment.

FIG. 2D illustrates a second layer of material for use in the gapbetween two magnetic layers of material, in accordance with oneembodiment.

FIG. 2E illustrates a sacrificial layer of material disposed over theinitial gap materials, in accordance with one embodiment.

FIG. 2F illustrates the sacrificial layer after processing has occurredthat created an uneven surface to the sacrificial layer, in accordancewith one embodiment.

FIG. 2G illustrates further deposition of sacrificial layer material toform an even top surface to the sacrificial layer, in accordance withone embodiment.

FIG. 2H illustrates a second magnetic material layer disposed above thesacrificial layer, in accordance with one embodiment.

FIG. 3 shows a flow chart illustrating a method of forming asubstantially uniform gap layer, in accordance with one embodiment.

FIG. 4 shows a flow chart illustrating another embodiment of forming agap layer, in accordance with one embodiment.

FIG. 5 shows a flow chart illustrating a method of utilizing anon-magnetic seed layer in accordance with one embodiment.

FIG. 6 shows a flow chart illustrating another embodiment of utilizing anon-magnetic seed layer in accordance with one embodiment.

FIG. 7 shows a cross-section of a write gap for a write head having atleast two layers of non-magnetic material in the write gap, inaccordance with one embodiment.

DETAILED DESCRIPTION

Embodiments of the present technology are disclosed herein in thecontext of a disc drive system. However, it should be understood thatthe technology is not limited to a disc drive system and could readilybe applied to other technology systems as well.

As areal density of magnetic recording media increases, more and morebits of information are being stored on the magnetic media. Thus, thereis a need to store each bit of information in a smaller storage locationthan has previously been used. As a result, the write head of a discdrive needs to be able to record the bit on the magnetic media withoutdisrupting the information stored in neighboring bit locations.

Write heads can be inefficient if there is a lack of a uniform gapbetween the magnetic material of the write pole and the magneticmaterial of the front shield. This non-uniformity allows more magneticflux to leak from the write pole to the front shield during a writeoperation—rather than being directed through the targeted bit location.As a result, the write pole is less efficient in its write operationwhen this leakage occurs. A more uniform gap or even a gap that divergesrather than converges (when viewed from the perspective of movingtowards an air bearing surface) would cause less leakage to occur.

In accordance with one embodiment a new process is disclosed that allowsone to form a substantially uniform write gap between two magneticmaterials as well as a resulting writer structure for a recording head.A magnetic overlayer with appropriate seeds (magnetic or non-magnetic)may also be formed on top of a non-magnetic write gap immediatelyfollowing the deposition of any write gap layers of material. The writegap, together with the magnetic overlayer may be tailored to form aunique structure. In accordance with one embodiment, the process may beused to form a substantially uniform write gap, to reduce the gapthickness sigma, and to improve write performance of a write head with anarrow write gap. A deliberately selected non-magnetic seed may be usedto enable a high moment magnetic layer to be in direct contact with awrite gap without sacrificing the magnetic softness of the high momentmagnetic materials. Moreover, configuring the material on both sides ofthe gap to have high moments without changing the magnetic softness ofthe magnetic materials can help to achieve improved writability. Whilethe embodiments described as examples herein use a write head as anexample, the process and structures may also be applied to othermagnetic layers that are separated by a gap of material.

With reference now to FIG. 1, an example of a disc drive system isshown. A disc drive system is but one example where disclosed technologymay be utilized. FIG. 1 illustrates a perspective view 100 of anexample. A disc 102 rotates about a spindle center or a disc axis ofrotation 104 during operation. The disc 102 includes an inner diameter106 and an outer diameter 108 between which are a number of concentricdata tracks 110, illustrated by circular lines. The data tracks 110 aresubstantially circular.

Information may be written to and read from the bits on the disc 102 indifferent data tracks 110. A transducer head 124 is mounted on anactuator assembly 120 at an end distal to an actuator axis of rotation122. The transducer head 124 flies in close proximity above the surfaceof the disc 102 during disc operation. The actuator assembly 120 rotatesduring a seek operation about the actuator axis of rotation 122positioned adjacent to the disc 102. The seek operation positions thetransducer head 124 over a target data track of the data tracks 110.

The exploded view 140 illustrates a cross-section of a portion of thetransducer head 124 (not to scale). The cross-section shows asubstantially uniform write-gap that can be configured in accordancewith one embodiment.

As the areal density of magnetic recording media increases, informationcan be stored in smaller and smaller locations. This requires that theread head and write heads be able to read from and write to,respectively, those locations. A write gap is the non-magnetic gapseparating the main writer pole from the front shield in a write head.The thickness of the write gap and the magnetic materials that are inthe vicinity of the write gap can have great impact upon the writabilityand the trailing edge (TE) field gradient. To date, the write gapthicknesses are in the range of about 30 nm.

During the process of forming write gaps, it is not uncommon to performphotolithography and etch processes on the deposited write gap material.This results in the write gap being deteriorated unevenly across itssurface. Where the write gap contains a bevel edge, one result is thatthe write gap can become tapered or pinched near the top of the bevelpoint. Thus, a non-uniform write gap is often produced by thesephotolithography and etching steps. A non-uniform write gap can resultin more flux shunt to the front shield from the main writer pole duringoperation. This loss of flux makes a write operation less efficient andpossibly defective. It can be referred to as suppressing writability.

Referring now to FIGS. 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H a process forforming a more uniform write gap can be illustrated in accordance withone embodiment. This process may also be used to reduce the write gapsigma. It will also be appreciated from the following description thatthis process enables an alternative seed, such as Ruthenium, to be usedas a seed layer for the 2.4 T FeCo layer of the front shield. Moreover,such a seed layer allows a FeCo magnetic layer to be in intimate contactwith the write gap in order to provide an enhanced TE field gradient.

In FIG. 2A a first layer of magnetic material 204 is deposited. Themagnetic material may be formed, for example, from FeCo. This layer ofmagnetic material may ultimately serve as the main write pole duringoperation of a write head. To form the main write pole, one may bevelthe magnetic material layer 204 to form a bevel edge 208 and a bevelpoint 212, as shown in FIG. 2B. The bevel may be formed by milling themagnetic layer, for example.

In FIG. 2C, a first layer of gap material 216 is shown deposited on thetop of the magnetic material layer 204. One type of material that may beutilized is Ruthenium. Ruthenium is a non-magnetic material that canperform well as a gap material. It can also serve as a seed layer for asecond layer of gap material.

In FIG. 2D, a second layer of gap material 220 is shown as deposited onthe top of the first layer of gap material. One material that can beuseful as a gap material is Al₂O₃ also referred to as alumina.

In FIG. 2E, a first layer of sacrificial material is shown as depositedon the top of the second layer of gap material. Oftentimes, one willchoose to perform photolithography and etching steps before depositingthe final layer of magnetic material. Such processing steps can affectthe uniformity of the gap materials that have previously beendeposited—particularly in the bevel edge region. One non-uniformity thatcan take place is that the write gap becomes tapered at the bevel point.As noted earlier, this can result in a non-uniform write-gap in afinished write head that causes decreased performance by the write head.Examples of processing steps that are often performed include aphotolithography step that is followed by an etching step. Otherprocessing steps might alternatively be performed. Regardless, theresult is that the write gap is left in a non-uniform state. Byutilizing a sacrificial layer that can be refurbished by deposition ofadditional sacrificial material, the uniformity of the gap can besubstantially restored following the damaging processing steps. Thus,FIG. 2F shows the effects of the damaging processing steps on thesacrificial layer 224. As can be seen, the damaging processing stepsleave the sacrificial layer in an uneven state, while the underlying gaplayers are undamaged. It should be noted that the sacrificial layer maybe seeded by a seed layer. One choice of seed layer material isRuthenium. Other non-magnetic seed material may be used rather thanRuthenium.

In FIG. 2G, additional sacrificial material may be deposited so as torestore the sacrificial layer to a substantially uniform thickness. Therestored sacrificial layer is referred to as layer 226 in FIG. 2G. Thesacrificial layer can also be selected so as to serve as a seed layerfor a subsequent magnetic layer.

Once the gap is restored to a substantially uniform thickness, a secondlayer of magnetic material may be deposited. For example, FIG. 2H showsa second layer of magnetic material 228 that may be used as a frontshield for a write head. One may utilize FeCo or FeNiCo solid solutionsas the magnetic material, for example. The thickness may be in the rangeof a few nanometers to a few hundreds of nanometers. In accordance withone embodiment, a thickness of 5-50 nm may be used.

As can be seen from FIG. 2H, the resulting write gap is substantiallyuniform and is not affected by the intermediate photolithography andetching steps that take place before the deposition of the second layerof magnetic material.

Referring now to FIG. 3, a flow chart 300 illustrating aspects of theabove-described process can be seen. In block 302, a non-magnetic gaplayer of material may be deposited above a main pole layer of magneticmaterial. In block 304, a sacrificial layer of material may be depositedabove the non-magnetic gap layer of material. In block 306, a portion ofthe sacrificial layer may be processed, for example by an etch process,while not entirely removing the sacrificial layer of material. And, inblock 308, additional sacrificial material may be deposited to theetched sacrificial layer.

In FIG. 4, a flow chart 400 illustrates a more detailed embodiment. Inblock 402, a non-magnetic layer of material is deposited above a mainpole layer of magnetic material. The main pole layer of magneticmaterial may already be in a beveled configuration. It should beappreciated that multiple layers and different materials may be used toform the gap. Block 404 illustrates that a sacrificial layer of materialmay be deposited on top of the top non-magnetic gap layer of material.

According to block 406, an etch or other processing step may beperformed on the structure. Such processing may remove portions of thesacrificial layer while not necessarily removing the entire sacrificiallayer so as to expose any underlying layers, particularly along thebevel edge area. The result of the etching or other processing will bethat the sacrificial layer will be uneven. Thus, in block 408,additional sacrificial material may be deposited on the etchedsacrificial layer. The deposition can be controlled so as to form asubstantially uniform gap between the main pole layer and a subsequentlyapplied front shield layer, as shown in block 410. Then, a front shieldlayer of material may be applied on top of the sacrificial layer.

In accordance with another embodiment, a different utility can beachieved. Namely, current processes typically utilize a magneticmaterial such as NiFe as a seed layer prior to depositing a layer ofmagnetic material, such as FeCo, as the front shield layer. The NiFe hasa magnetic moment property of about 1.0 T. This use of magnetic materialas the seed layer can degrade the trailing edge (TE) field gradientwhich in turn decreases the performance of the recording head.

To address this issue, one embodiment utilizes a non-magnetic materialas the seed layer for the magnetic material used in the front shieldlayer. This non-magnetic material allows a better field gradient to beachieved in contrast to a magnetic material such as NiFe. Differentmaterials may be utilized as the non-magnetic material seed layer. But,one possible choice is Ruthenium. Other possible materials are NiRu,NiCr, Cu, and high moment material with combinations of Fe, Ni, and Coalloys, for example. The thickness of the seed layer can be in the rangeof 1-10 nm, for example.

The deposition process can be similar to that shown with respect toFIGS. 2A through 2H where a non-magnetic seed layer is utilized for asecond layer of magnetic material. Moreover, FIG. 5 illustrates a flowchart demonstrating various aspects.

In flow chart 500 of FIG. 5, block 502 shows that a main pole layer ofmagnetic material is deposited. In block 504, at least two non-magneticgap layers of material are deposited. And, in block 506, a second layerof magnetic material is deposited. Notably, the second layer of magneticmaterial is deposited directly adjacent to the upper layer ofnon-magnetic gap material. This allows the non-magnetic gap material toserve as a seed layer for the second layer of magnetic material.

FIG. 6 illustrates a somewhat more detailed embodiment. In flow chart600 of FIG. 6, a main pole layer of magnetic material is deposited, inblock 602. In block 604, at least two non-magnetic gap layers ofmaterial are deposited. As noted in an earlier embodiment, the gap maybe formed from multiple layers, such as a first layer of Rutheniumfollowed by a layer of Al₂O₃, and followed by a seed layer of Ruthenium.

In block 606, a second layer of magnetic material may be deposited. Thislayer may be used, for example, as a front shield in a write head. Thissecond layer may be deposited directly adjacent the non-magnetic gapmaterial so as to form a sufficient gradient. Moreover, thisnon-magnetic gap material may be used as a seed layer for the secondlayer of magnetic material, as shown by block 608. As shown by block610, FeCo may be utilized as the material for the second layer ofmagnetic material. Block 612 illustrates that the second layer ofmagnetic material may be formed into a front shield for use in a writehead.

FIG. 7 illustrates an example of a gap layer that is formed from two ormore gap layers of non-magnetic material. FIG. 7 shows a first layer ofmagnetic material 702 that serves as the write head. FeCo is one type ofmagnetic material that can be used for the first magnetic layer 702. Afirst gap layer of non-magnetic material 704 is shown disposed above anddirectly adjacent to the magnetic material 702. One material that can beused, for example, is Ruthenium. A second gap layer of non-magneticmaterial 706 is shown disposed above and directly adjacent the first gaplayer 704. For example, Al₂O₃ is one type of material that could be usedfor this material. A third gap layer of non-magnetic material 708 isshown disposed above and directly adjacent the second gap layer 706. Thematerial Ruthenium could be utilized for this layer to provide symmetrywith the first gap layer 704. Moreover, Ruthenium is useful in servingas a seed layer for the second layer of magnetic material 710. The layer710 is shown disposed above and directly adjacent to the third gap layer708. FeCo is one example of a magnetic material that can be used forlayer 710 in order to serve as a front shield for the main pole.

It is noted that many of the structures, materials, and acts recitedherein can be recited as means for performing a function or step forperforming a function. Therefore, it should be understood that suchlanguage is entitled to cover all such structures, materials, or actsdisclosed within this specification and their equivalents, including anymatter incorporated by reference.

It is thought that the apparatuses and methods of embodiments describedherein will be understood from this specification. While the abovedescription is a complete description of specific embodiments, the abovedescription should not be taken as limiting the scope of the patent asdefined by the claims.

What is claimed is:
 1. An apparatus having an air-bearing surface, theapparatus comprising: a main pole layer of magnetic material; a secondlayer of magnetic material; a write gap disposed between the main polelayer and the second layer of magnetic material and extending to but notperpendicular to the air-bearing surface, the write gap comprising: afirst gap layer of Ruthenium; and a second gap layer of non-magneticmaterial directly adjacent to the second layer of magnetic material; anda third gap layer of non-magnetic material comprising Al₂O₃ between thefirst gap layer and the second gap layer.
 2. The apparatus as claimed inclaim 1 wherein the second gap layer of non-magnetic material isRuthenium, NiRu, NiCr, Cu, or a high moment material with combinationsof Fe, Ni, or Co.
 3. The apparatus as claimed in claim 1 wherein amagnetic moment on a first side of the write gap and a magnetic momenton a second side of the write gap are substantially equivalent.
 4. Theapparatus as claimed in claim 1 wherein the second layer of magneticmaterial forms a front shield.
 5. The apparatus as claimed in claim 1wherein the second gap layer of non-magnetic material serves as a seedlayer for the second layer of magnetic material.
 6. The apparatus asclaimed in claim 1 wherein the second layer of magnetic materialcomprises FeCo.
 7. The apparatus as claimed in claim 1, wherein thesecond gap layer of non-magnetic material has a thickness of 1-10 nm. 8.A method comprising: depositing a main pole layer of magnetic material;providing a bevel on the main pole layer; depositing a first gap layerof Ruthenium on the beveled main pole layer; depositing a second gaplayer of non-magnetic material comprising Al₂O₃; depositing a third gaplayer of non-magnetic material; depositing a second layer of magneticmaterial directly adjacent to the third gap layer of non-magneticmaterial.
 9. The method as claimed in claim 8 wherein the third gaplayer of non-magnetic material is Ruthenium, NiRu, NiCr, Cu, or a highmoment material with combinations of Fe, Ni, or Co.
 10. The method asclaimed in claim 8 and further comprising: forming a first magneticmoment on a first side of a write gap and a second magnetic moment on asecond side of the write gap wherein the first magnetic moment and thesecond magnetic moment are substantially equivalent.
 11. The method asclaimed in claim 8 and further comprising: forming a front shield fromthe second layer of magnetic material.
 12. The method as claimed inclaim 8 wherein depositing a third gap layer of non-magnetic materialcomprises depositing a third gap layer comprising Ruthenium.
 13. Themethod as claimed in claim 8 and further comprising: utilizing the thirdgap layer of non-magnetic material as a seed layer for the second layerof magnetic material.
 14. The method as claimed in claim 8 and furthercomprising: utilizing FeCo as the second layer of magnetic material. 15.The method as claimed in claim 8, wherein depositing a third gap layerof non-magnetic material comprises depositing 1-10 nm of thenon-magnetic material of the third gap layer.
 16. An apparatus having anair-bearing surface, the apparatus comprising: a main pole layer ofmagnetic material; a second layer of magnetic material; a write gapdisposed between the main pole layer and the second layer of magneticmaterial and extending to but not perpendicular to the air-bearingsurface, the write gap comprising: a first gap layer of Ruthenium, asecond gap layer of Ruthenium, and a third gap layer of Al₂O₃ betweenthe first gap layer and the second gap layer.